Python Tests: Fix long Numpy Type (#1348)

Ref.:
https://numpy.org/doc/stable/user/basics.types.html

Author: ax3l

test/python/unittest/API/APITest.py

@@ -2048,7 +2048,7 @@ def testError(self):
     def testCustomGeometries(self):
         DS = io.Dataset
         DT = io.Datatype
-        sample_data = np.ones([10], dtype=np.long)
+        sample_data = np.ones([10], dtype=np.int_)
 
         write = io.Series("../samples/custom_geometries_python.json",
                           io.Access.create)